Richard Doherty, director at consultant Envisioneering Group told Business Week that eventually iPhone users may even get a commission if they induce someone else to make a purchase.
When confronted about this possibility, Apple spokeswoman Jennifer Bowcock would not discuss future features with the site, saying only, "We've made no announcements at this time."
This information comes just after it was discovered that Apple will no longer allow the redownloading of iPhone applications from the device itself. You must re-download applications using your computer; otherwise, you will have to pay full price for the app again.
This seems to contradict the App Sharing idea; however, it's possible that it's just a part of an overall system that Apple is implementing.